GateGuru has joined forces with Kayak to bring their database of airport amenities to the Kayak iPhone app.

As a quick reminder – GateGuru has the most comprehensive airport amenity guide in the world – and it currently covers all US airports along with a growing lineup of international locations.

With the addition of this new feature, the Kayak app has (in my opinion) become the best all-in-one travel app there is on the iPhone.

From within Kayak, you can now search for fares, find hotels and rental cars, check flight status, look up airline fees and phone numbers, store trips from Kayak.com, set up fare alerts and more.

Best of all – the Kayak app is still free of charge (a “first class” version is available for $1.99 if you need access to business and first class fares).

If you want to take full advantage of GateGuru for features like ratings, ranks and social media updates, you’ll still need the separate app, but having instant access to this information from within Kayak is still a really neat feature.